Mainframe computer



FIG. 1 is a top front and right side perspective view of a mainframe computer showing our new design;

FIG. 2 is a top rear and left side perspective view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a rear elevational view thereof; and,

FIG. 7 is a left side elevational view thereof. 

The ornamental design for a mainframe computer, as shown. 